Field of the Invention
The present invention relates to leno selvaging and stretch nozzle systems, and in particular, to leno selvaging and stretch nozzle systems for use with air jet textile looms.
Selvage systems are utilized with looms to hold the loose ends of filling yarns extending outwardly from the edges of the woven fabric and to facilitate removal of the waste fringe of yarn at the edges of the fabric. Typical leno selvage systems, such as in a Ruti L5000 air jet loom, utilize what is known as a false selvage system. In general, a plurality of warp yarns are disposed in parallel, extending through a comb-like reed mechanism reciprocally mounted on the lay of the loom. The warp yarns are held either in relatively high or relatively low elevational positions to establish a space, referred to as a shed, just downstream of the reed. A filling yarn is directed through the shed between the respective sets of upper and lower warp yarns, and is "beaten up" against the already woven yarns by the reciprocating reed. The elevational positions of the individual warp yarns are reversed at predetermined intervals to weave the filling yarns and warp yarns into a fabric. Loom temples are provided at the edges of the fabric to keep the fabric from bunching during the beating process. At the outer edges of the warp yarns, (the edges of the fabric) respective inner sets of leno yarns are provided, which prevent unraveling of the fabric edges. However, in order to facilitate the cutting of the fringe of filling yarns extending beyond the edge of the inner leno yarns, a second (outer) set of leno yarns are provided, spaced apart from the inner set of leno yarns. The space between the inner and outer leno yarns is typically referred to as a skip dent. The outer leno yarns are woven with and bind the filling yarns, and are utilized to carry away the fringe waste. A cutting mechanism is disposed in the skip dent area to trim the fringe at the edge of the fabric to an acceptable length.
It is necessary to keep the filling yarn taut during the beating process. In conventional air jet looms such as the Ruti L5000, such tensioning is achieved utilizing a stretch nozzle disposed on the end of the reed, and a wide-mouthed suction nozzle fixed on the loom proximate to the end of the reed. Specifically, the stretch nozzle is disposed on the lay outside of the outer leno yarn. A sequenced pulsating jet of air is applied to one side of the nozzle, and suction applied at the other to draw a portion of the filling yarn upwardly into the nozzle, in a direction transverse to the filling yarn. Thus, tension is provided to pull the yarn taut. The end of the filling yarn is received and held in the wide-mouthed nozzle by suction. Separate air pressure and vacuum sources are utilized. It should be appreciated that the vacuum systems utilize substantial amounts of energy during continued operation of the loom, and tend to require frequent maintenance and filter replacement.
A minimum necessary length of the fringe waste is maintaining tension on the filling yarn. Typically, the fringe waste is shorter on the left side of the loom and longer on the right side, in order to accommodate the tensioning mechanisms. As a matter of economy it is desirable to minimize the length of the fringe waste. It is also desirable to remove any lint or the like from the filling yarn prior to beating by the reed.